Interpretive Summary: Plant viruses are an important constraint on wheat production in the Great Plains. One of the most significant is Wheat streak mosaic virus (WSMV). Until recently, high resistance to WSMV was not available, however, a variety, RonL, was released with high resistance. In the spring of 2006, a plot of RonL was found to have WSMV like symptoms. Initially, it was thought that the virus symptoms were due to a variant of the WSMV virus or High Plains virus. Using diagnostic techniques, it was found that the symptoms were due to a new, uncharacterized virus. A coat protein covers most plant viruses and the amino acid sequence of the new virus’ coat protein was different that any other virus characterized. Thus, the virus was given the name Triticum mosaic virus (TriMV). In the associated report, the complete sequence of the RNA of the virus is reported and compared to other wheat-infecting viruses. There is strong evidence that the virus belongs to the Potyvirus family but the evidence also shows that it is distantly related to WSMV. Future work will look at collections from across the Great Plains to determine whether TriMV is a new introduction, or has been present, but just undetected.

Technical Abstract:
In the spring of 2006, a new virus was isolated from wheat grown in Western Kansas. Virion structure and the coat protein amino acid sequence suggested that the virus was similar to those in the Potyvirus family, but not closely related to any previously characterized isolate. A tentative name was given as Triticum mosaic virus (TriMV). The objective of this work was to sequence the complete virus, characterize the sequence and determine to which family it belongs. TriMV has a complete mRNA strand of 9479 nucleotides to the first adenosine of the polyA tail. The predicted polyprotein consists of 3040 amino acids and protease sites are present that lead to nine predicted mature peptides. Amino acid alignments demonstrate that the complete virus is most closely related to Sugarcane streak mosaic virus based on 53.5% identity in amino acid sequence, but less than 24% identical to other Tritimoviruses. Of all of the nine predicted mature proteins, the NIb-RNA dependent RNA polymerase is the most conserved amongst other wheat infecting Potyviruses, while the HC-Pro is the most diverse. Therefore, evidence is strong to place TriMV in the Potyvirus family, but is diverse enough to be unclassified.